The majority of electronic equipment produced presently includes miniaturized active components and circuitry to perform high-speed functions and utilize high speed electrical interconnections to propagate power and data between critical components. These components can be very susceptible to stray electrical energy created by electromagnetic interference or voltage transients occurring on electrical circuitry servicing or utilizing these systems. Voltage transients can severely damage or destroy such micro-electronic components or contacts thereby rendering the electronic equipment inoperative, often requiring extensive repair and/or replacement at a great cost.
Electrical interference in the form of EMI, RFI and capacitive and inductive parasitics can be created or induced into electrical circuitry and components from such sources as radio broadcast antennas or other electromagnetic wave generators. EMI can also be generated from the electrical circuit, which makes shielding from EMI desirable. Differential and common mode currents are typically generated in cables and on circuit board tracks. In many cases, fields radiate from these conductors which act as antennas. Controlling these conducted/radiated emissions is necessary to prevent interference with other circuitry that is sensitive to the unwanted noise. Other sources of interference are also generated from equipment as it operates, coupling energy to the electrical circuitry, which may generate significant interference. This interference must be eliminated to meet international emission and/or susceptibility requirements.
Transient voltages can be induced by lightning on electrical lines producing extremely large potentials in a very short time. In a similar manner, electromagnetic pulses (EMP) can generate large voltage spikes with fast rise time pulses over a broad frequency range that are detrimental to most electronic devices. Other sources of large voltage transients as well as ground loop interference caused by varying ground potentials can disrupt an electrical system. Existing protection devices are unable to provide adequate protection in a single integrated package. Varieties of filter and surge suppression circuit configurations have been designed as is evident from the prior art. A detailed description of the various inventions in the prior art is disclosed in U.S. Pat. No. 5,142,430, herein incorporated by reference.
The '430 patent itself is directed to power line filter and surge protection circuit components and the circuits in which they are used to form a protective device for electrical equipment. These circuit components comprise wafers or disks of material having desired electrical properties such as varistor or capacitor characteristics. The disks are provided with electrode patterns and insulating bands on the surfaces thereof, which coact with apertures, formed therein, so as to electrically connect the components to electrical conductors of a system in a simple and effective manner. The electrode pattern coact with one another to form common electrodes with the material interposed between. The '430 patent was primarily directed toward filtering paired lines. Electrical systems have undergone short product life cycles over the last decade. A system built just two years ago can be considered obsolete to a third or fourth generation variation of the same application. Accordingly, componentry and circuitry built into these the systems need to evolve just as quickly.
The performance of a computer or other electronic systems has typically been constrained by the speed of its slowest active elements. Until recently, those elements were the microprocessor and the memory components that controlled the overall system's specific functions and calculations. However, with the advent of new generations of microprocessors, memory components and their data, there is intense pressure to provide the user increased processing power and speed at a decreasing unit cost. As a result, the engineering challenge of conditioning the energy delivered to electrical devices has become both financially and technologically difficult. Since 1980, the typical operating frequency of the mainstream microprocessors has increased approximately 240 times, from 5 MHz (million cycles per second) to approximately to 1200 MHz+by the end of the year 2000. Processor speed is now matched by the development and deployment of ultra-fast RAM architectures. These breakthroughs have allowed boosting of overall system speeds past the 1 GHz mark. During this same period, passive componentry technologies have failed to keep up and have produced only incremental changes in composition and performance. Advances in passive component design changes have focused on component size reduction, slight modifications of discrete component electrode layering, new dielectric discoveries, and modifications of manufacturing production techniques that decrease component production cycle times.
In the past, passive component engineers have solved design problems by increasing the number of components in the electrical circuit. These solutions generally involved adding inductors and resistors that are used with capacitors to filter and decouple.
Not to be overlooked, however, is the existence of a major limitation in the line conditioning ability of a single passive component and for many passive component networks. This limitation presents an obstacle for technological progression and growth in the computer industry and remains as one of the last remaining challenges of the+GHz speed system. This constraint to high-speed system performance is centered upon the limitations created by the supporting passive componentry that delivers and conditions energy and data signals to the processors, memory technologies, and those systems located outside of a particular electronic system.
The increased speed of microprocessors and memory combinations has resulted in another problem as evidenced by recent system failures that have occurred with new product deployments of high-speed processors & new memory combinations by major OEMs. The current passive component technology is the root cause of many of these failures and delays. The reasons are that the operating frequency of a single passive component generally has a physical line conditioning limitation of between 5 and 250 MHz. Higher frequencies for the most part require combinations of passive elements such as discrete L-C-R, L-C, R-C networks to shape or control energy delivered to the system load. At frequencies above 200 MhZ, prior art, discrete L-C-R, L-C, R-C networks begin to take on characteristics of transmission lines and even microwave-like features rather than providing lump capacitance, resistance or inductance that such a network was designed for. This performance disparity between the higher operating frequency of microprocessors, clocks, power delivery bus lines and memory systems and that of the supporting passive elements has resulted in system failures.
Additionally, at these higher frequencies, energy pathways are normally grouped or paired as an electrically complementary element or elements that electrically and magnetically must work together in harmony and balance An obstacle to this balance is the fact that two discrete capacitors manufactured in the same production batch can easily posses a variability in capacitance, ranging anywhere from 15%-25%. While it is possible to obtain individual variations of capacitance between discrete units of less than 10%, a substantial premium must be paid to recover the costs for testing, hand sorting manufactured lots, as well as the additional costs for the more specialized dielectrics and manufacturing techniques that are needed to produce these devices with reduced individual variance differences required for differential signaling. Therefore, in light of the foregoing deficiencies in the prior art, the applicant's invention is herein presented.